FIle Upload VB.NET

Here is my html

<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="cc1" %>
<%@ MasterType virtualpath="~/MasterPages/Speaker.master" %>

the control

<asp:UpdatePanel ID="pnlUpload" runat="server">
		<ContentTemplate>
			<table>
				<cc1:AsyncFileUpload ID="fuSlides" Width="400px" runat="server"
				OnClientUploadError="uploadError" 
				OnClientUploadStarted="StartUpload" 
				OnClientUploadComplete="UploadComplete" 
				CompleteBackColor="Lime"
				UploaderStyle="Modern" 
				ErrorBackColor="Red" 
				onuploadedcomplete="fuSlides_UploadedComplete" 
				UploadingBackColor="#66CCFF" />
			</table>
			<br>
			</br>
			<asp:Label ID="lblStatus" runat="server" Text="Label"></asp:Label>
		</ContentTemplate>	
	</asp:UpdatePanel>

the javascript

 <script type="text/javascript" language="javascript">
	     function uploadError(sender, args) {
	         alert("[" + lblStatus + "]"); return false;
	         document.getElementById('lblStatus').innerHTML = args.get_errorMessage();
		 }
	     function StartUpload(sender, args) {
	         alert("[" + fuSlides + "]"); return false;
			 var filename = args.get_fileName();
			 var filext = filename.substring(filename.lastIndexOf(".") + 1);
			 if (filext == "doc" || filext == "docx" || filext == "pdf" || filext == "pages" || filext == "pptx" || filext == "ppt") {
				 return true;
			 }
			 else {
				 var err = new Error();
				 err.name = 'My API Input Error';
				 err.message = 'Only .ppt, .pptx, .doc, .docx, or .pdf  files';
				 throw (err);

				 return false;
			 }
		 }
	    function UploadComplete(sender, args) {;
			var filename = args.get_fileName();
			var contentType = args.get_contentType();
			var text = "Size of " + filename + " is " + args.get_length() + " bytes";
			if (contentType.length > 0) {
				text += " and content type is '" + contentType + "'.";
			}
		}
</script>